Canvas: The #10 duck or canvas is heavier than 10 ounce duck or canvas. Depending on the supplier, #10 fabric seems to be 13 to 15 ounces per yard, or about 40 percent heavier than a 10 ounce fabric. For comparison, Levi's heaviest jeans are made from 11 or 12 ounce fabric. (I suppose denim could be used, and if you got it in blue you wouldn't have to paint it, now would you? But then what does one do about waterproofing it?)

I got two batches of canvas, the cheapest was from Jo-Ann Fabric's upholstery area, and the more expensive was from Clark Craft. The difference was about $2 a yard. Despite the additional cost, I like the heavier weight of the material from Clark Craft. I'm saving it ot use on the "real" boat. The lighter weight fabric (10 ounce) has been on the test frame I built, and has been outside for a couple of years. It seems to be perfectly fine after it is coated, so I am expecting the heavier material to be even better.

Clark Craft sells 100% copper tacks for canoe and kayak building. Very reasonable price. You'll need about 1/4 pound, and that sells for about $3. consider finding a friend to pull the canvas taut while you drive tacks. If you can't find the proper canvas pliers, electricians pliers have been used, too.

Linseed oil (plain, boiled and stand) can be found at artist supply stores, as can the canvas pliers.

Utrecht art supply (www.utrecht.com) also has artist canvas and linen ( linen is very expensive) in heavy weights, long lengths, and wide widths. Their C D 10 ( cotton duck #10, I'd guess) is 14 3/4 ounce material. A 6 yard package of 60 inch wide material is $50.94. 10 yards is $84.90. They also have a lighter weight material (#12) for a bit less money. This is 11 4/10 ounce material, which is still a bit heavier than 10 ounce fabric from the fabric stores.

try this link to their canvas pages:

http://www.utrechtart.com/dsp_display_prod.cfm?p=w67178&g=w67178

If you want wider canvas (72 inches wide) then try Dick Blick art suplies ( www.dickblick.com) They want about $13.50 a yard, but you can probably get two boats out of material this wide.

consider using a lighter weight canvas for the deck. You don't need the 14 ounce material there, 10 ounce material is just fine.

The Snow Roof materials appear to be quite thick in the can, but you don't need to thin this before using. Like latex paint, it goes on thin and smooth. Even after 4 or 5 coats the weave is still visible. this stuff was meant for coating roofs. Its UV resistance is tremendous, and a thick coat will harden in the sun to form a very durable rubber layer over your fabric.

last year I painted over it with a marine enamel and like the look, however, the marine enamel is not a flexible as the cnavas, and it cracks, with many tiny, fine, cracks radiating form areas where I have poked and prodded. That doesn't meant the boat will leak, though, as the under layer of Snow Roof appears to be just fine.

The manner in which I have stored my test seems conducive to mildew growth. The snow roof materials alone do not protect the canvas. I'll add a mildew preventative material to the snow roof next time I use it.

hope this helps.

Paul G. Jacobson